According to the results of the calculations of scientists, the average person spends in a dream about 24 years in his life. That is, we sleep almost a third of our life. Our health, mood, performance depends on how we sleep, — everything that is now customary to call the «quality of life». And, in turn, what we sleep on, also seems to us very significant. Mattress is what we are directly lying for several hours in a row during sleep.